I'm running 5.5b5. I believe this is an issue that started (or became worse) with the 5.5 beta versions, but for my Vive (SteamVR) unity project, I get regular VR.WaitForGPU spikes and these happen even if I disable every game object (including the camera) in my scene. For every spike the Vive drops a frame which looks terrible. Even the Vive demo scene does this. Have others experiences this? Is there any trick for getting around this?